Semiconductor radioactive wafer decay safety and operation system

Abstract

A radiation safety apparatus for a semiconductor processing system has a safety fence with a support frame and radiation shields defining containment regions associated with load ports of the semiconductor processing system. The containment regions are associated with radioactive sources that emit radioactive radiation, where radiation shields attenuate the radiation to a region external to the containment regions. The radiation shields have access doors movably coupled to the support frame to provide access to the containment regions. Interlocks are provided with the access doors to selectively lock the access doors in a closed position to control the access to the containment regions from the external region through the access doors. A controller controls the interlocks based on a radiation decay associated with each of the radioactive sources and a predetermined safe radiation exposure level.

What is claimed is: 
     
         1 . A radiation safety apparatus for a semiconductor processing system, the radiation safety apparatus comprising:
 a safety fence comprising:
 a support frame; and 
 a plurality of radiation shields operatively coupled to the support frame and defining one or more containment regions, wherein the one or more containment regions are associated with one or more load ports of the semiconductor processing system, and wherein the one or more containment regions are further respectively associated with one or more radioactive sources that emit radioactive radiation, wherein the plurality of radiation shields are configured to attenuate the radioactive radiation to an external region that is external to the one or more containment regions, and wherein the plurality of radiation shields further comprise one or more access doors movably coupled to the support frame, wherein the one or more access doors are configured to provide selective access between the one or more containment regions and the external region; 
   one or more interlocks operatively coupled to the one or more access doors, wherein the one or more interlocks are configured to selectively lock the one or more access doors in a closed position, respectively, thereby controlling the selective access to the one or more containment regions from the external region through the one or more access doors; and   a controller configured to control the one or more interlocks based on a predetermined radiation decay associated with each of the one or more radioactive sources and a predetermined safe radiation exposure level.   
     
     
         2 . The radiation safety apparatus of  claim 1 , wherein controller is further configured to control the one or more interlocks based on an operational condition of the semiconductor processing system. 
     
     
         3 . The radiation safety apparatus of  claim 1 , wherein the predetermined radiation decay is based on a model. 
     
     
         4 . The radiation safety apparatus of  claim 1 , further comprising a plurality of wheels operatively coupled to the support frame, whereby the support frame is selectively moveable with respect to the one or more load ports via the plurality of wheels. 
     
     
         5 . The radiation safety apparatus of  claim 1 , wherein the safety fence comprises a front side, a rear side, a left side, a right side, and a top side, wherein the plurality of radiation shields define the front side, the left side, and the right side of the safety fence. 
     
     
         6 . The radiation safety apparatus of  claim 5 , wherein the rear side is operatively coupled to the semiconductor processing system via an equipment front end module (EFEM). 
     
     
         7 . The radiation safety apparatus of  claim 5 , wherein the one or more access doors comprise two or more access doors, and wherein the plurality of radiation shields define two or more containment regions respectively associated with the two or more access doors, wherein the plurality of radiation shields comprise one or more intermediate shields positioned between each of the two or more access doors, wherein the one or more intermediate shields extend from the front side toward the rear side and further attenuate the radioactive radiation between the one or more containment regions. 
     
     
         8 . The radiation safety apparatus of  claim 5 , wherein the top side is open to an overhead region, whereby the one or more load ports of the semiconductor processing system are accessible from the top side. 
     
     
         9 . The radiation safety apparatus of  claim 1 , further comprising one or more front opening unified pods (FOUPs) associated with each of the one or more load ports of the semiconductor processing system, whereby the one or more radioactive sources comprise radioactive semiconductor wafers contained within the one or more FOUPs. 
     
     
         10 . An ion implantation system comprising:
 an ion source configured to form and accelerate an ion beam at a high energy;   a beamline assembly configured to selectively control one or more properties of the ion beam;   an end station configured receive the ion beam for implantation of ions into one or more wafers, wherein the high energy of the ion beam induces a fusion reaction within the one or more wafers, thereby defining one or more radioactive sources that emit radioactive radiation;   one or more load ports operatively coupled to the end station and configured to selectively transfer the one or more radioactive sources to one or more front opening Unified Pods (FOUPs);   a radiation safety apparatus operatively coupled to the end station, the radiation safety apparatus comprising:   a safety fence comprising:
 a support frame; and 
 a plurality of radiation shields operatively coupled to the support frame and defining one or more containment regions, wherein the one or more containment regions are associated with the one or more load ports, and wherein the one or more containment regions are further respectively associated with the one or more FOUPs, wherein the plurality of radiation shields are configured to attenuate the radioactive radiation from the one or more radioactive sources to an external region that is external to the one or more containment regions, and wherein the plurality of radiation shields further comprise one or more access doors movably coupled to the support frame, wherein the one or more access doors are configured to provide selective access between the one or more containment regions and the external region; 
   one or more interlocks operatively coupled to the one or more access doors, wherein the one or more interlocks are configured to selectively lock the one or more access doors in a closed position, respectively, thereby controlling the selective access to the one or more containment regions from the external region through the one or more access doors; and   a controller configured to control the one or more interlocks based on a modelled radiation decay associated with each of the one or more radioactive sources and a predetermined safe radiation exposure level.   
     
     
         11 . The ion implantation system of  claim 10 , wherein the controller is further configured to control the one or more interlocks based on an operational condition of one or more of the ion source, the beamline assembly, and the end station. 
     
     
         12 . The ion implantation system of  claim 10 , wherein the radiation safety apparatus further comprises a plurality of wheels operatively coupled to the support frame, whereby the support frame is selectively moveable with respect to the one or more load ports via the plurality of wheels. 
     
     
         13 . The ion implantation system of  claim 10 , wherein the safety fence defines a front side, a rear side, a left side, a right side, and a top side, wherein the plurality of radiation shields define the front side, the left side, and the right side of the safety fence, and wherein the rear side is operatively coupled to the end station. 
     
     
         14 . The ion implantation system of  claim 13 , wherein the one or more access doors comprise two or more access doors, and wherein the plurality of radiation shields define two or more containment regions respectively associated with the two or more access doors, wherein the plurality of radiation shields comprise one or more intermediate shields positioned between each of the two or more access doors, wherein the one or more intermediate shields extend from the front side toward the rear side and further attenuate the radioactive radiation between the one or more containment regions. 
     
     
         15 . The ion implantation system of  claim 13 , wherein the top side is open to an overhead region, whereby the one or more FOUPs are accessible from the top side. 
     
     
         16 . The ion implantation system of  claim 10 , further comprising an equipment front end module (EFEM) operatively coupled to the end station, wherein the EFEM is configured to selectively contain the one or more FOUPs, and wherein the radiation safety apparatus is operatively coupled to the EFEM. 
     
     
         17 . A method for ameliorating radiation exposure in ion implantation processing, the method comprising:
 providing a plurality of front opening unified pods (FOUPs);   positioning a safety fence with respect to an equipment front end module (EFEM) of an ion implantation system, wherein a plurality of radiation shields of the safety fence define a plurality of containment regions associated with a plurality of load ports of the EFEM;   positioning a first FOUP of the plurality of FOUPs with respect to a first load port of the plurality of load ports in a first containment region of the plurality of containment regions, wherein the first FOUP contains a first plurality of wafers;   transferring the first plurality of wafers from the first FOUP through the first load port into the ion implantation system;   modeling a radiation activation of the first plurality of wafers based on ion implantation parameters associated with the ion implantation system to define a first radiation decay time associated with a predetermined safe radiation exposure level;   implanting ions into the first plurality of wafers at a high energy, thereby inducing nuclear fusion in the first plurality of wafers to define a first plurality of radioactive wafers;   preventing access to the first FOUP via the safety fence from an external region concurrent with implanting the ions into the first plurality of wafers;   transferring the first plurality of radioactive wafers to the first FOUP;   preventing access to the first FOUP through the safety fence from the external region until the first radiation decay time lapses; and   permitting access to the first FOUP through the safety fence only after the first radiation decay time lapses.   
     
     
         18 . The method of  claim 17 , further comprising transferring the first FOUP through a top opening of the safety fence via an overhead hoist transport (OHT) after the first radiation decay time lapses. 
     
     
         19 . The method of  claim 17 , wherein preventing access to the first FOUP comprises locking an access door associated with the first containment region, and wherein permitting access to the first FOUP comprises unlocking the access door. 
     
     
         20 . The method of  claim 17 , further comprising:
 positioning a second FOUP of the plurality of FOUPs with respect to a second load port of the plurality of load ports in a second containment region of the plurality of containment regions, wherein the second FOUP contains a second plurality of wafers;   transferring the second plurality of wafers from the second FOUP through a second load port into the ion implantation system;   modeling a radiation activation of the second plurality of wafers based on the ion implantation parameters associated with the ion implantation system to define a second radiation decay time associated with the predetermined safe radiation exposure level;   implanting ions into the second plurality of wafers at the high energy, thereby inducing nuclear fusion in the second plurality of wafers to define a second plurality of radioactive wafers;   preventing access to the second FOUP via the safety fence from an external region concurrent with implanting the ions into the second plurality of wafers;   transferring the second plurality of radioactive wafers to the second FOUP;   preventing access to the second FOUP through the safety fence from the external region until the second radiation decay time lapses; and   permitting access to the second FOUP through the safety fence only after second radiation decay time lapses.